#include<iostream>
#include<vector>
#include<array>
int main()
{
    using namespace std;
    double a1[]={1.2,2.4,3.5,7.8};
    vector<double> a2(4);
    a2[0]=1/3;
    a2[1]=2/3;
    a2[2]=4/3;
    a2[3]=5/3;
    array<double,4> a3={3.14,4.52,7.85,7.21};
    array<double,4> a4;
    a4=a3;
    cout<<"a1[2]:"<<a1[2]<<" at "<<&a1[2]<<endl;
    cout<<"a2[2]:"<<a2[2]<<" at "<<&a2[2]<<endl;
    cout<<"a3[2]:"<<a3[3]<<" at "<<&a3[2]<<endl;
    cout<<"a4[2]:"<<a4[2]<<" at "<<&a4[2]<<endl;
    }